Vehicle fuel systems include evaporative emission control systems designed to reduce the release of fuel vapors to the atmosphere. For example, vaporized hydrocarbons (HCs) from a fuel tank may be stored in a fuel vapor canister packed with an adsorbent which adsorbs and stores the vapors. At a later time, when the engine is in operation, the evaporative emission control system allows the vapors to be purged into the engine intake manifold for use as fuel.
Diverting fuel vapor located in the fuel tank to the fuel vapor canister prior to refueling is especially important for hybrid electric vehicles (HEVs). Such vehicles are designed to run primarily on an electric motor and only occasionally use the internal combustion engine, resulting in fewer opportunities to purge the fuel vapor canister. Furthermore, HEVs feature a fuel tank isolation valve that seals the fuel tank in order to maintain fuel vapor within the tank during vehicle operations. Without regular purging of the evaporative emission system, normal vaporization of the liquid fuel in the tank will cause the tank to become pressurized above atmospheric pressure. Prior to a refueling event, fuel tank vapor needs to be vented to the fuel vapor canister in order to prevent evaporative emissions via the fuel filler neck. Further, an overpressurized tank could result in liquid fuel splashing out of the tank when opened.
In order to lower the fuel tank pressure to atmospheric pressure prior to refueling and therefore prevent fuel vapors from escaping into the atmosphere, HEVs come equipped with a dashboard-mounted refuel request button that a driver must press prior to refueling. Requesting a refueling event triggers a controller to open the fuel tank isolation valve, depressurizing the fuel tank prior to allowing access to the fuel filler neck. However, the location of these refuel request buttons on the dashboard is unintuitive and inconvenient. If a driver forgets to press the button prior to exiting the vehicle at the refueling station, he or she must re-enter the vehicle in order to prepare the vehicle for refueling. Further, a refueling operator approaching the refueling door from the outside of the vehicle has no control over the tank depressurization process.
The inventors herein have recognized the above described problems, and have developed systems and methods to at least partially address these issues. In one example, a method for a vehicle, comprising: depressurizing a fuel tank while restricting access to a fuel fill line responsive to receiving a refueling request from a refueling request module located external to a vehicle cabin; and allowing access to the fuel fill line responsive to the fuel tank pressure decreasing below a threshold. In this way, all of the steps of a refueling procedure can be carried out entirely outside of a vehicle.
In another example, a fuel system for a vehicle, comprising: a fuel tank; a refueling inlet configured to receive a fuel dispensing nozzle; a fuel fill line coupled between the refueling inlet and the fuel tank; a refueling door located in a body panel of the vehicle and configured to restrict access to the refueling inlet; a refueling lock coupled to the refueling door; and a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to: responsive to the refueling door being displaced inwards, initiate a fuel tank depressurization sequence while maintaining the refueling door locked; and then allow access to the fuel fill line responsive to the fuel tank depressurizing below a pressure threshold. In this way, all of the refueling hardware can be located in one area. This in turn reduces the complexity and cost of the design.
In yet another example, a method for a vehicle, comprising: receiving a voltage signal from a potentiometer indicating a refueling request, the refueling request comprising an operator inwardly pressing a refueling door configured to engage the potentiometer; depressurizing a fuel tank while maintaining the refueling door locked; unlocking the refueling door when a fuel tank pressure is below a pressure threshold; receiving a voltage signal from the potentiometer indicating the refueling door is open; receiving a voltage signal from the potentiometer indicating the refueling door is closed; and sealing the fuel tank and locking the refueling door responsive to receiving the voltage signal from the potentiometer indicating the refueling door is closed. In this way, a refueling operator may simply push in the refueling door in order to begin the refueling process.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.